Candidate: Dr. Adams completed her DVM cum laude at Texas A&M University, and she completed her Ph.D. in immunology in Dr. Douglas Antczak's laboratory at Cornell University, studying mechanisms of fetal evasion from maternal immune responses. Dr. Adams will apply her skills as an immunologist to pursue her long-term goal of understanding the pathogenesis of alphaviral encephalitides, knowledge that will ultimately be used for development of effective vaccines/therapeutics. The proposed project is designed to bridge her transition from an Instructor to a permanent academic post in comparative medicine research. Research: Venezuelan equine encephalitis virus (VEEV) is a naturally emerging arbovirus that threatens human health throughout the Americas. Human epidemics only occur when there is efficient amplification of VEEV in equids. VEEV is also considered a potential bioterrorist agent, categorized by the NIAID as a Category B Priority Pathogen. A recent outbreak of an epizootic subtype IE VEEV underscores the continued threat of VEE emergence in human populations and what little we know about its ability to amplify in equids and alter virulence via mutations. The objective of this proposal is to dissect the role of structural and nonstructural proteins of epizootic subtype IE VEEV in causing efficient equine amplification, neurovirulence, and immune modulation. Specific aim 1: Identify genetic determinants of VEEV amplification and cell tropism using parental and chimeric strains of epizootic/enzootic subtype IE VEEV. As early cell targets of VEEV infection, equine macrophages/dendritic cells (DCs) will be tested for their ability to support viral replication. Equine peripheral blood leukocytes (PBLs) will also be examined for viral replication in vivo during early infection. Specific aim 2: Identify genetic determinants of VEEV pathogenicity and immunogenicity using parental and chimeric strains of epizootic/enzootic subtype IE VEEV. Infected equine macrophage/DC cultures will be tested for altered innate/adaptive immune responses using interferon (IFN) bioassays, quantitative RT-PCR of cytokines (including type I IFNs), and cDNA microarrays for global gene regulation. Neurologic symptoms will be quantitatively assessed in experimentally infected equids;neural/extraneural tissues will be qualitatively/quantitatively examined for gross/histopathologic lesions. Sera from infected animals will be measured for IFN induction, and PBLs and lymphoid/non-lymphoid tissues will be analyzed for altered gene expression of cytokines using quantitative RT-PCR. Collectively, these experiments will advance understanding of VEE emergence mechanisms and reveal natural determinants of amplification/virulence. Environment: Dr. Adams'project complements current, NIH-funded research of her proposed sponsor, Dr. Scott Weaver. The primary site of training, the University of Texas Medical Branch (UTMB), has superb facilities and equipment and outstanding faculty who study various aspects of arboviruses, including comparative medicine, immunology, and vaccine development. PUBLIC HEALTH RELEVANCE: Venezuelan equine encephalitis virus (VEEV) is the cause an important zoonotic disease that occurs throughout the Americas, with the demonstrated capacity to cause explosive outbreaks affecting hundreds-of- thousands of people and equids. Major epidemics in humans only occur when VEEV replicates to high titers in the blood of infected horses, donkeys, and mules, which is then transmitted to humans by infected mosquitoes. Using a VEEV isolate from a recent outbreak in Mexico, the purpose of the proposed study is identify viral genes that are responsible for efficient replication and neurovirulence in horses, which is critically important for the successful development of future intervention strategies (i.e., vaccines, therapeutics, and other human disease control measures).